Merge pull request chainguard-dev#1111 from chainguard-dev/R

feat: Add build pipeline for R packages

docs/PIPELINES-R.md

@@ -0,0 +1,95 @@
+# Built-in R pipeline
+
+Melange includes a built-in pipeline to compile R packages.
+
+To get started quickly, checkout the `R/build` pipeline:
+[cran-build.yaml](https://github.com/chainguard-dev/melange/blob/main/examples/R-build.yaml)
+
+## Building R packages with `R/build`
+
+The `R/build` pipeline is a declarative interface that leverages the R package
+manager. This pipeline builds an R package from source and installs it to the
+standard R library directory.
+
+Here's a sample melange configuration file cloning and running the same
+sample project as above:
+
+```yaml
+package:
+  name: cran-proxy
+  version: 0.4_27
+  epoch: 0
+  description: Distance and similarity measures
+  copyright:
+    - license: GPL-2.0-or-later
+
+environment:
+  contents:
+    packages:
+      - R
+      - R-dev
+      - busybox
+
+var-transforms:
+  - from: ${{package.version}}
+    match: '_'
+    replace: '-'
+    to: mangled-package-version
+
+pipeline:
+  - uses: git-checkout
+    with:
+      repository: https://github.com/cran/proxy
+      tag: ${{vars.mangled-package-version}}
+      expected-commit: 311a8569a534460ef04473ffa442dc7b72ba9a41
+
+  - uses: R/build
+    with:
+      package: proxy
+      version: ${{vars.mangled-package-version}}
+
+  - uses: strip
+
+update:
+  enabled: true
+  version-transform:
+    - match: '_'
+      replace: '-'
+  github:
+    identifier: cran/proxy
+    use-tag: true
+```
+
+(:bulb: Experiment with this code, 
+[download it from the examples directory](https://github.com/chainguard-dev/melange/blob/main/examples/R-build.yaml))
+
+## Build Parameters
+
+The `R/build` pipeline supports passing a few parameters the R package manager by
+setting them in the melange configuration file. As of this writing, you can define
+the following values:
+
+```yaml
+  package:
+    description: |
+      The R package to install
+    required: true
+
+  path:
+    description: |
+      Path to R package source or source tarball
+    default: "."
+
+  version:
+    description: |
+      The R package version
+    required: true
+```
+
+For the most up to date supported features check the
+[build](https://github.com/chainguard-dev/melange/blob/main/pkg/build/pipelines/R/build.yaml)
+pipeline.
+
+Feel free to request more features in the built-in pipelines by
+[filing a new issue](https://github.com/chainguard-dev/melange/issues/new) in 
+the melange repository!

examples/R-build.yaml

@@ -0,0 +1,51 @@
+# SPDX-FileCopyrightText: 2024 Chainguard, Inc
+# SPDX-License-Identifier: Apache-2.0
+#
+# This is a sample configuration file to demonstrate how to build a software
+# project using melange's built-in R/build pipeline.
+#
+# For more information about melange's built-in rust support check out:
+# https://github.com/chainguard-dev/melange/blob/main/docs/PIPELINES-R.md
+package:
+  name: cran-proxy
+  version: 0.4_27
+  epoch: 0
+  description: Distance and similarity measures
+  copyright:
+    - license: GPL-2.0-or-later
+
+environment:
+  contents:
+    packages:
+      - R
+      - R-dev
+      - busybox
+
+var-transforms:
+  - from: ${{package.version}}
+    match: '_'
+    replace: '-'
+    to: mangled-package-version
+
+pipeline:
+  - uses: git-checkout
+    with:
+      repository: https://github.com/cran/proxy
+      tag: ${{vars.mangled-package-version}}
+      expected-commit: 311a8569a534460ef04473ffa442dc7b72ba9a41
+
+  - uses: R/build
+    with:
+      package: proxy
+      version: ${{vars.mangled-package-version}}
+
+  - uses: strip
+
+update:
+  enabled: true
+  version-transform:   
+    - match: '_'
+      replace: '-'
+  github:
+    identifier: cran/proxy
+    use-tag: true

pkg/build/pipelines/R/build.yaml

@@ -0,0 +1,35 @@
+name: Run a build using the R package manager
+
+needs:
+  packages:
+    - R
+    - R-dev
+    - busybox
+
+inputs:
+  package:
+    description: |
+      The R package to install
+    required: true
+
+  path:
+    description: |
+      Path to R package source or source tarball
+    default: "."
+
+  version:
+    description: |
+      The R package version
+    required: true
+
+pipeline:
+  - runs: |
+      # Use default R library path
+      mkdir -p /usr/lib/R/library
+      mkdir -p ${{targets.contextdir}}/usr/lib/R/library
+
+      # Build R package from source
+      Rscript -e 'install.packages("${{inputs.path}}", repos = NULL, type = "source")'
+
+      # Install package
+      mv /usr/lib/R/library/${{inputs.package}} ${{targets.contextdir}}/usr/lib/R/library/